Light-emitting device and electronic device using the same

ABSTRACT

A lightweight flexible light-emitting device which is able to possess a curved display portion and display a full color image with high resolution and the manufacturing process thereof are disclosed. The light-emitting device comprises: a plastic substrate; an insulating layer with an adhesive interposed therebetween; a thin film transistor over the insulating layer; a protective insulating film over the thin film transistor; a color filter over the protective insulating film; an interlayer insulating film over the color filter; and a white-emissive light-emitting element formed over the interlayer insulating film and being electrically connected to the thin film transistor.

TECHNICAL FIELD

The present invention relates to a light-emitting device which has acircuit including a thin film transistor (hereinafter referred to as aTFT). Further, the present invention relates to an electronic device onwhich the light-emitting device is mounted.

BACKGROUND ART

In recent years, a technological development has been remarkably made inthe field of displays. Especially, the needs of market has stimulatedtremendous progress in the technology directed to increase in resolutionand thinning of displays.

In a next phase, focus is placed on commercialization of a flexibledisplay having a curved display portion. Indeed, a variety of proposalshave been made on manufacturing the flexible display (for example, seePatent Document 1). The use of a flexible substrate enables reduction inweight of a light-emitting device compared with the use of a glasssubstrate.

However, such a flexible display is also required to have high imagequality.

A variety of factors influence the image quality. For instance,improvement in resolution is effective for improvement of image quality.

-   [Patent Document 1] Japanese Patent Laid-Open No. 2003-204049.

DISCLOSURE OF INVENTION

However, a flexible substrate is readily deformed and twisted due to itsflexibility. Therefore, an attempt to obtain full color display using aflexible substrate possesses a difficulty in precise and selectiveformation of light-emitting layers and color filters in an appropriateregion of a display portion.

It is an object to supply a flexible light-emitting device which is ableto have a curved display portion, has lightweight, and simultaneouslycan display a full color image with high resolution.

The foregoing problem can be solved by forming an element formationlayer comprising a color filter and a thin film transistor over a planesubstrate with a plate-like shape, such as a glass substrate, and thenforming a white-emissive light-emitting element after transferring theelement formation layer to a plastic substrate.

Namely, an embodiment of the invention is a light-emitting devicecomprising: a plastic substrate; an insulating layer formed over theplastic substrate with an adhesive sandwiched between the plasticsubstrate and the insulating layer; a thin film transistor formed overthe insulating layer; a protective insulating film formed over the thinfilm transistor; a color filter formed over the protective insulatingfilm; an interlayer insulating film formed over the color filter; and awhite-emissive light-emitting element formed over the interlayerinsulating film and electrically connected to the thin film transistor.Such a light-emitting device is able to display a full color image withhigh resolution in spite of its flexibility.

Another embodiment of the invention is a light-emitting devicecomprising: a plastic substrate; an insulating layer formed over theplastic substrate with an adhesive sandwiched between the plasticsubstrate and the insulating layer; a thin film transistor formed overthe insulating layer; a first protective insulating film formed over thethin film transistor; a color filter formed over the first protectiveinsulating film; a second protective insulating film formed over thecolor filter; an interlayer insulating film formed over the secondprotective insulating film; and a white-emissive light-emitting elementwhich is formed over the interlayer insulating film and electricallyconnected to the thin film transistor. The light-emitting device is ableto display a full color image with high resolution in spite of itsflexibility. Additionally, the light-emitting device having thisstructure possesses improved reliability since the white-emissivelight-emitting element is protected by the second protective insulatingfilm from a gas released from the color filter.

Note that, in the above-mentioned structure, a light-emitting device isalso included in an embodiment of the invention in which patterning ofthe color filter is performed to allow the color filter to be placed ina position corresponding to a first pixel electrode of thewhite-emissive light-emitting element, and the first protectiveinsulating film and the second protective insulating film are in contactwith each other in a vicinity of the color filter. The light-emittingdevice allows the white-emissive light-emitting element and the thinfilm transistor to be effectively protected from contamination resultingfrom degasification from the color filter and so on. Thus, alight-emitting device with more improved reliability can be obtained.

Note that it is preferred that the above-mentioned protective insulatingfilm is a silicon nitride film because the silicon nitride film is ableto more effectively block a contaminant and suppress degasification.

An embodiment of the invention is a light-emitting device comprising: aplastic substrate; a first insulating layer formed over the plasticsubstrate with an adhesive sandwiched between the plastic substrate andthe first insulating layer; a color filter formed over the firstinsulating layer; a thin film transistor formed over a second insulatinglayer which is formed so as to cover the color filter; and awhite-emissive light-emitting element formed over the thin filmtransistor and electrically connected to the thin film transistor. Evensuch a light-emitting device with this structure can be flexible anddisplay a full color image with high resolution.

It is preferred that, in the light-emitting device with theabove-mentioned structure, a semiconductor layer of the thin filmtransistor is formed of amorphous silicon, an organic semiconductor, anoxide semiconductor, or microcrystalline silicon since the thin filmtransistor is formed after forming the color filter.

The light-emitting devices of the embodiments of the invention candisplay a full color image with high resolution although they areflexible light-emitting devices.

BRIEF DESCRIPTION OF DRAWINGS

In the accompanying drawings:

FIGS. 1A to 1C are views each showing a light-emitting device of anembodiment of the invention;

FIG. 2 is a view showing a light-emitting device of an embodiment of theinvention;

FIGS. 3A to 3D are diagrams showing a manufacturing process of alight-emitting device of an embodiment of the invention;

FIGS. 4A and 4B are views showing a light-emitting device of anembodiment of the invention;

FIGS. 5A to 5E are views each showing an electronic device according toan embodiment of the invention;

FIGS. 6A to 6C are views each explaining a structure of a light-emittinglayer;

FIGS. 7A and 7B are views each explaining a structure of alight-emitting layer; and

FIG. 8 is a view explaining a structure of a light-emitting element.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below withreference to the accompanying drawings. However, the present inventioncan be carried out in many different modes. As is easily known to aperson skilled in the art, the mode and the detail of the invention canbe variously changed without departing from the spirit and the scope ofthe invention. Therefore, the present invention is not to be construedwith limitation to what is described in the embodiment modes.

DETAILED DESCRIPTION OF THE INVENTION Embodiment 1

A light-emitting device of an embodiment of the invention ischaracterized in that an element formation layer comprising a TFT, anelectrode of a light-emitting element, and the like is supported by aplastic substrate through an adhesive and that a color filter isprovided between the plastic substrate and the light-emitting element.

The light-emitting device having such a structure can be manufactured bythe following method and the like. First, the element formation layerincluding the TFT, the color filter, and a first pixel electrode of thelight-emitting element is formed over a substrate with low flexibility,such as a substrate formed of glass, ceramics, and the like, with aseparation layer sandwiched between the element formation layer and thesubstrate. Next, the substrate and the element formation layer areseparated from each other at the separation layer, and the separatedelement formation layer is bonded to the plastic substrate using theadhesive.

As to the light-emitting device manufactured in this way, the colorfilter is formed using the substrate having low flexibility. Therefore,even in the case of a pixel arrangement directed to a full color displayin high resolution, misalignment of the color filter is negligible,which allows the formation of a flexible display capable of displaying afull color image with high resolution.

Note that a protective insulating film may be provided over the colorfilter in order to reduce adverse influence of degasification from thecolor filter upon the light-emitting element.

FIGS. 1A to 1C each illustrate a view showing the light-emitting deviceof the present embodiment.

In the light-emitting device shown in FIG. 1A, an adhesive 111 isprovided over a plastic substrate 110. The adhesive 111 is provided soas to be in contact with an insulating layer 112, allowing an elementformation layer 113 and the plastic substrate 110 to be bonded to eachother. In the element formation layer 113, a pixel TFT 114, a TFT 115 ina driving circuit portion, a color filter 116, a first pixel electrode117 of a light-emitting element 121 electrically connected to the pixelTFT 114, and a partition layer 118 are provided. FIG. 1A illustrates apart of these members. The light-emitting element 121 is formed of thefirst pixel electrode 117 exposed from the partition layer 118, an ELlayer 119 which overlaps at least the first pixel electrode 117 andcontains a light-emitting substance, and a second pixel electrode 120which overlaps the EL layer 119.

Light emitted from the light-emitting element 121 is preferably red,green, blue, or white. The EL layer 119 and the second pixel electrode120 of the light-emitting element 121 are formed after the elementformation layer 113 is bonded to the plastic substrate 110. Note thatsince the EL layer 119 and the second pixel electrode 120 of thelight-emitting element 121 are formed over all pixels in common,misalignment in the formation thereof does not provide a serious problemalthough they are formed using the plastic substrate 110.

In the light-emitting devices shown in FIGS. 1A to 1C, the color filter116 is formed after the TFTs are formed. Note that it is preferred thatthe color filter 116 is formed over a first protective insulating film122 which is provided over the TFTs since the first protectiveinsulating film 122 is able to protect the TFTs from a contaminantreleased from the color filter 116.

FIG. 1B shows a structure in which a second protective insulating film123 is provided over the color filter 116. This structure enables theproduction of a light-emitting device with higher reliability becauseadverse influence of degasification from the color filter 116 upon thelight-emitting element 121 can be reduced.

FIG. 1C illustrates a structure in which the color filter 124 ispatterned to be located on a position corresponding to the first pixelelectrode 117 of the light-emitting element. In this structure, at leastin a vicinity of the color filter 124, the first protective insulatingfilm 122 and the second protective insulating film 123 which covers thecolor filter 124 are in contact with each other, which allows the colorfilter 124 to be completely surrounded by the protective insulatingfilms. Therefore, diffusion of the contaminant from the color filter124, such as a gas, can be more effectively prevented. Note that it ispreferred that the first protective insulating film 122 and the secondprotective insulating film 123 are formed by using the same material.Moreover, these protective insulating films are preferably formed byusing silicon nitride or silicon oxynitride which has a composition ofnitrogen higher than that of oxygen.

Next, a manufacturing process of the light-emitting device of thisembodiment is explained with reference to FIGS. 3A to 3D and FIGS. 1A to1C.

First, the element formation layer 113 comprising the TFT, the colorfilter, the first pixel electrode, and the like is formed over thesubstrate 200 having an insulating surface with a separation layer 201interposed between the element formation layer 113 and the substrate 200(see, FIG. 3A).

As the substrate 200, a glass substrate, a quartz substrate, a sapphiresubstrate, a ceramic substrate, a metal substrate over which aninsulating layer is formed, and the like can be used. In themanufacturing process of the light-emitting device, the substrate 200can be selected as appropriate in accordance with the conditions of theprocess.

Since a substrate with low flexibility, which is frequently used in themanufacture of usual displays, is used as the substrate 200, the pixelTFT and the color filter can be placed in an arrangement suitable for ahigh-resolution display.

The separation layer 201 is formed by a sputtering method, a plasma CVDmethod, a coating method, a printing method, or the like, so as to haveeither a single-layer structure or a stacked structure by using anelement selected from tungsten (W), molybdenum (Mo), titanium (Ti),tantalum (Ta), niobium (Nb), nickel (Ni), cobalt (Co), zirconium (Zr),zinc (Zn), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os),iridium (Ir), and silicon (Si); an alloy containing these elements as amain component; or a compound containing these elements as a maincomponent. A crystal structure of a layer containing silicon may beamorphous, microcrystal, or polycrystal. Note that the coating methodincludes a spin-coating method, a droplet discharge method, a dispensingmethod, a nozzle printing method, and a slot die coating method in itscategory here.

In the case that the separation layer 201 has a single-layer structure,it is preferred to form a tungsten layer, a molybdenum layer, a layercontaining a mixture of tungsten and molybdenum, a layer containing anoxide or an oxynitride of tungsten, a layer containing an oxide or anoxynitride of molybdenum, or a layer containing an oxide or anoxynitride of a mixture of tungsten and molybdenum as the separationlayer 201. Note that the mixture of tungsten and molybdenum correspondsto an alloy of tungsten and molybdenum, for example.

In the case where the separation layer 201 has a stacked structure, atungsten layer, a molybdenum layer, or a layer containing a mixture oftungsten and molybdenum is formed as a first layer, and a layercontaining: an oxide, a nitride, an oxyntride, or a nitride oxide oftungsten; an oxide, a nitride, an oxyntride, or a nitride oxide ofmolybdenum; or an oxide, a nitride, an oxyntride, or a nitride oxide ofa mixture of tungsten and molybdenum is formed as a second layer.

In the case where the stacked layer of a layer containing tungsten and alayer containing an oxide of tungsten is formed as the separation layer201, the layer containing tungsten may be formed first, which isfollowed by the formation of an insulating layer formed of an oxide (forexample, a silicon oxide layer) over the layer containing tungsten sothat a layer containing an oxide of tungsten is formed at the interfacebetween the tungsten layer and the insulating layer. Further, a surfaceof the tungsten layer may be subjected to thermal oxidation treatment,oxygen plasma treatment, or treatment with a strong oxidizing solutionsuch as water containing ozone to form the layer containing the oxide oftungsten. Further, plasma treatment or heat treatment may be performedin an atmosphere of oxygen, nitrogen, dinitrogen monoxide, or a mixedgas of these gases and another gas. The formation of a layer containinga nitride, an oxynitride, and a nitride oxide of tungsten can besimilarly performed. Specifically, after forming the layer includingtungsten, an insulating layer formed of a nitride, an oxynitride, or anitride oxide (for example, a silicon nitride layer, a siliconoxynitride layer, or a silicon nitride oxide layer) is preferably formedover the layer including tungsten.

The insulating layer to be a base can be formed as a single layer or astacked layer by using an inorganic insulating film such as siliconoxide, silicon nitride, silicon oxynitride, silicon nitride oxide, orthe like.

As a material of the semiconductor layer included in the TFT, anamorphous semiconductor (hereinafter referred to as “AS”), apolycrystalline semiconductor, a microcrystalline semiconductor(semiamorphous or microcrystal, hereinafter referred to as “SAS”), asemiconductor which has an organic material as a main component, or thelike can be used. The semiconductor layer can be formed by a sputteringmethod, an LPCVD method, a plasma CVD method, or the like.

Note that the microcrystalline semiconductor belongs to a metastablestate which is an intermediate between an amorphous state and a singlecrystal state according to Gibbs free energy. That is, themicrocrystalline semiconductor is a semiconductor having a third statewhich is stable in terms of free energy and has a short range order andlattice distortion. In the microcrystalline semiconductor, columnar-likeor needle-like crystals grow in a normal direction with respect to asurface of a substrate. The Raman spectrum of microcrystalline silicon,which is a typical example of a microcrystalline semiconductor, isshifted to a small wavenumber region below 520 cm⁻¹ which corresponds tothe wavenumber of the Raman spectrum peak of single-crystalline silicon.That is, the peak of the Raman spectrum of the microcrystalline siliconexists between 520 cm⁻¹ which represents single-crystalline silicon and480 cm⁻¹ which represents amorphous silicon. The microcrystallinesemiconductor includes at least 1 at. % of hydrogen or halogen toterminate a dangling bond. Moreover, a rare gas element such as helium,argon, krypton, or neon may be included to further promote latticedistortion, so that stability is enhanced and a favorablemicrocrystalline semiconductor film can be obtained.

The microcrystalline semiconductor film can be formed by ahigh-frequency plasma CVD method with a frequency of several tens toseveral hundreds of megahertz or a microwave plasma CVD method with afrequency of 1 GHz or more. Typically, the microcrystallinesemiconductor film can be formed by using a gas obtained by diluting asilicon hydride or a silicon halide, such as SiH₄, Si₂H₆, SiH₂Cl₂,SiHCl₃, SiCl₄, SiF₄, or the like, with hydrogen. Additionally, themicrocrystalline semiconductor film can be formed by using a gascontaining a silicon hydride and hydrogen which is diluted by rare gaselements selected from helium, argon, krypton, and neon. In this case,the flow rate of hydrogen is set to be greater than or equal to 5 timesand less than or equal to 200 times, preferably greater than or equal to50 time and less than or equal to 150 times, much more preferably 100times as much as that of silicon hydride.

A hydrogenated amorphous silicon can be typically exemplified as theamorphous semiconductor, while a polysilicon or the like can betypically exemplified as a crystalline semiconductor layer. Examples ofpolysilicon (polycrystalline silicon) include so-called high-temperaturepolysilicon that contains polysilicon as a main component and is formedat a process temperature greater than or equal to 800° C., so-calledlow-temperature polysilicon that contains polysilicon as a maincomponent and is formed at a process temperature less than or equal to600° C., polysilicon obtained by crystallizing amorphous silicon byusing an element that promotes crystallization or the like, and thelike. Note that as mentioned above, a microcrystalline semiconductor ora semiconductor containing a crystal phase in part of a semiconductorlayer may be used.

As a material of the semiconductor, as well as an element of silicon(Si), germanium (Ge), or the like, a compound semiconductor such asGaAs, InP, SiC, ZnSe, GaN, SiGe, or the like can be used. Alternatively,an oxide semiconductor such as zinc oxide, tin oxide, magnesium zincoxide, gallium oxide, indium oxide, an oxide semiconductor formed of aplurality of the above oxide semiconductors, and the like may be used.For example, an oxide semiconductor formed of zinc oxide, indium oxide,and gallium oxide may be used. In the case of using zinc oxide for thesemiconductor layer, a gate insulating film is preferably formed usingyttrium oxide, aluminum oxide, titanium oxide, a stack of any of theabove substances, or the like. For a gate electrode layer, a sourceelectrode layer, and a drain electrode layer, ITO, Au, Ti, or the likeis preferably used. In addition, In, Ga, or the like can be added intozinc oxide.

In the case of using a crystalline semiconductor layer for thesemiconductor layer, the crystalline semiconductor layer may be formedby any of various methods (such as a laser crystallization method, athermal crystallization method, a thermal crystallization method usingan element promoting crystallization such as nickel), and the like.Also, a microcrystalline semiconductor, which is an SAS, can becrystallized by irradiating laser light to increase its crystallinity.In a case where an element which promotes crystallization is not used,before the amorphous silicon film is irradiated with a laser beam, theamorphous silicon film is heated at 500° C. for one hour in a nitrogenatmosphere to reduce a hydrogen concentration in the amorphous siliconfilm to less than or equal to 1×10²⁰ atoms/cm³. This is because, if theamorphous silicon layer contains much hydrogen, the amorphous siliconlayer may be destroyed by laser beam irradiation.

Any method can be used for introducing a metal element into theamorphous semiconductor layer as long as the method allows the metalelement to exist on the surface of or inside the amorphous semiconductorlayer. For example, a sputtering method, a CVD method, a plasma processmethod (including a plasma CVD method), an adsorption method, a methodof applying a solution of a metal salt, or the like can be used. Amongthe above-mentioned processes, the method using a solution is convenientand has an advantage of easily adjusting the concentration of a metalelement. It is preferable to form an oxide film on the amorphoussemiconductor layer by UV light irradiation in an oxygen atmosphere, athermal oxidation treatment, treatment with ozone water or hydrogenperoxide including a hydroxyl radical, or the like in order to improvewettability of the surface of the amorphous semiconductor layer and tospread the aqueous solution over the entire surface of the amorphoussemiconductor layer.

The crystallization may be performed by adding an element which promotescrystallization (also referred to as a catalyst element or a metalelement) to an amorphous semiconductor layer and performing a heattreatment (at 550° C. to 750° C. for 3 minutes to 24 hours) in acrystallization step in which the amorphous semiconductor layer iscrystallized to form a crystalline semiconductor layer. As the elementwhich promotes (accelerates) the crystallization, one or more of iron(Fe), nickel (Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh), palladium(Pd), osmium (Os), iridium (Ir), platinum (Pt), copper (Cu), and gold(Au) can be used.

In order to remove or reduce the element promoting crystallization fromthe crystalline semiconductor layer, a semiconductor layer containing animpurity element is formed in contact with the crystalline semiconductorlayer and is made to function as a gettering sink. The impurity elementmay be an impurity element imparting n-type conductivity, an impurityelement imparting p-type conductivity, a rare gas element, or the like.For example, one or a plurality of elements selected from phosphorus(P), nitrogen (N), arsenic (As), antimony (Sb), bismuth (Bi), boron (B),helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) can beused. Specifically, the above-mentioned semiconductor layer containingthe impurity element is formed in contact with the crystallinesemiconductor layer containing the element which promotescrystallization, and heat treatment (at temperature ranging from 550 to750° C. for 3 minutes to 24 hours) is performed. The element thatpromotes crystallization in the crystalline semiconductor layer istransported to the semiconductor layer containing the impurity element;thus, the element that promotes crystallization in the crystallinesemiconductor layer is removed or reduced. After that, the semiconductorlayer containing the impurity element functioning as the gettering sinkis removed.

In addition, thermal treatment and laser light irradiation may becombined to crystallize the amorphous semiconductor layer. The thermaltreatment and/or the laser light irradiation may be independentlyperformed a plurality of times.

In addition, a crystalline semiconductor layer may be directly formedover the substrate by a plasma treatment method. Alternatively, thecrystalline semiconductor layer may be selectively formed over asubstrate by using a plasma treatment method.

As a semiconductor film mainly containing an organic material, asemiconductor film mainly containing carbon can be used. Specifically,pentacene, tetracene, thiophene oligomers, polyphenylenes,phthalocyanine compounds, polyacetylenes, polythiophenes, a cyanine dye,and the like are given as examples.

As to the gate insulating film and the gate electrode, a known structuremay be applied, and a known method may be used for the formationthereof. For instance, the gate insulating film may be formed accordingto a known structure such as a single layer of silicon oxide, a stackedstructure of silicon oxide and silicon nitride, and the like. The gateelectrode may be formed of an element selected from Ag, Au, Cu, Ni, Pt,Pd, Ir, Rh, W, Al, Ta, Mo, Cd, Zn, Fe, Ti, Si, Ge, Zr, and Ba; or analloy or a compound containing any of these elements as its maincomponent by using the CVD method, the sputtering method, the dropletdischarging method, or the like. Alternatively, a semiconductor filmtypified by a polycrystalline silicon film doped with an impurityelement such as phosphorus, or AgPdCu alloy may be used. Either a singlelayer structure or a layered structure may be applied.

Note that although an example is shown in FIGS. 1A to 1C in whichtransistors with a top-gate structure are used, a transistor with aknown structure such as a bottom-gate structure and the like may beused.

The first protective insulating film 122 is formed over the gateinsulating film and the gate electrode. The first protective insulatingfilm 122 may be formed of a silicon oxide layer, a silicon oxynitridefilm, a silicon nitride oxide film, or a silicon nitride film, or may beformed as a stacked film in which any of these films are combined. Inany case, the first protective insulating film 122 is formed of aninorganic insulating material. The formation of the first protectiveinsulating film 122 allows the reduction of pollution of the TFT causedby the color filter 116 formed later. The use of a silicon nitride filmor a silicon nitride oxide film which has a composition of nitrogenhigher than that of oxygen is preferred because the contaminant from thecolor filter 116 can be effectively blocked.

The color filter 116 is formed over the first protective insulating film122. Although a color filter with a single color is shown in FIGS. 1A to1C, a color filter which transmits red light, a color filter whichtransmits blue light, and a color filter which transmits green light areformed in an appropriate arrangement and shape. Any arrangement can beadopted for the arrangement of the color filter 116, including a stripepattern, a diagonal mosaic arrangement, a triangle mosaic arrangement,an RGBW four pixel arrangement, and the like. The RGBW four pixelarrangement is a pixel arrangement having: a pixel mounted with a colorfilter transmitting red light; a pixel mounted with a color filtertransmitting blue light; a pixel mounted with a color filtertransmitting green light; and a pixel without color filter, and iseffective in reducing power consumption and so on.

The color filter 116 can be formed by using a known material. In thecase of using a photosensitive resin as the color filter 116, patterningof the color filter 116 may be performed by exposing the color filter116 itself to light and then developed. It is preferred to performpatterning by dry etching when a minute pattern is formed.

After the formation of the color filter 116, an interlayer insulatingfilm formed using an organic insulating material is formed over thecolor filter 116. As the organic insulating material, an acrylic, apolyimide, a polyamide, a polyimidoamide, a benzocyclobutene-basedresin, and the like can be used.

The second protective insulating film 123 may be provided between thecolor filter 116 and the interlayer insulating film in order to suppressthe influence of degasification from the color filter 116 (see FIG. 1B).The second protective insulating film 123 can be formed with a similarmaterial to that of the first protective insulating film 122. It is apreferred structure in which the second protective insulating film 123is formed using a silicon nitride film or a silicon nitride oxide filmhaving a composition of nitrogen higher than oxygen since degasificationfrom the color filter 116 can be effectively suppressed. Note that astructure is preferred in which the first protective insulating film 122and the second protective insulating film 123 are in contact with eachother in a vicinity of the color filter 124 because influence of acontaminant and degasification can be more effectively suppressed (see,FIG. 1C). In this case, the use of the same material for the firstprotective insulating film 122 and the second protective insulating film123 allows the improvement of adhesion therebetween, which contributesto further reduction of influence of the contaminant and degasification.The reduction of influence of the contaminant and degasificationimproves reliability of the light-emitting device.

After the formation of the interlayer insulating film, the first pixelelectrode 117 is formed using a transparent conductive film. When thefirst pixel electrode 117 is an anode, indium oxide, an alloy of indiumoxide and tin oxide (ITO), and the like can be used as a material of thetransparent conductive film. Alternatively, an alloy of indium oxide andzinc oxide (IZO) may be used. In a similar manner, zinc oxide is also anappropriate material, and moreover, zinc oxide (GZO) to which gallium(Ga) is added to increase conductivity and transmissivity with respectto visible light may be used. When the first pixel electrode 117 is usedas a cathode, an extremely thin film of a material with a low workfunction such as aluminum can be used. Alternatively, a stackedstructure which has a thin layer of such a material and theabove-mentioned transparent conductive film can be employed. Note thatthe first pixel electrode 117 can be formed by a sputtering method, avacuum evaporation method, or the like.

Next, etching is performed on the interlayer insulating film, (thesecond protective insulating film 123), (the color filter 116), thefirst protective insulating film 122, and the gate insulating film toresult in formation of a contact hole which reaches the semiconductorlayer of the TFT. Then a conductive metal film is formed by a sputteringmethod or a vacuum evaporation method, which is followed by etching toresult in an electrode of the TFT and a wiring. One of a sourceelectrode and a drain electrode of the pixel TFT 114 is formed so as tooverlap with the first pixel electrode 117 in order to achieveelectrical connection therebetween.

After that, an insulating film is formed using an organic insulatingmaterial or an inorganic insulating material so that the insulating filmcovers the interlayer insulating film and the first pixel electrode 117.The insulating film is then processed to allow a surface of the firstpixel electrode 117 to be exposed and an end portion of the first pixelelectrode 117 to be covered by the insulating film, leading to theformation of the partition layer 118.

Through the above-mentioned process, the element formation layer 113 canbe formed.

Next, the element formation layer 113 and a provisional supportingsubstrate 202 are bonded to each other using a first adhesive 203, whichis followed by separation of the element formation layer 113 from thesubstrate 200 at the separation layer 201. By this process, the elementformation layer 113 is placed over the provisional supporting substrate202 (see, FIG. 3B).

As the provisional supporting substrate 202, a glass substrate, a quartzsubstrate, a sapphire substrate, a ceramic substrate, a metal substrateon which an insulating surface is formed, and the like can be used.Further, a plastic substrate which can resist a temperature of themanufacturing process of this embodiment or a flexible substrate such asa film may be used.

As the first adhesive 203 used here, an adhesive, which is soluble in asolvent such as water or is capable of plasticizing upon irradiation ofUV light, and the like, is used so that the provisional supportingsubstrate 202 can be chemically or physically separated from the elementformation layer 113 when necessary.

Any of following methods can be applied in the transferring process fromthe substrate 200 to the provisional supporting substrate 202: formingthe separation layer 201 between the substrate 200 and the elementformation layer 113, forming a metal oxide film between the separationlayer 201 and the element formation layer 113, embrittling the metaloxide film by crystallizing thereof, and separating the elementformation layer 113; forming an amorphous silicon film containinghydrogen between the substrate 200 having high thermal resistivity andthe element formation layer 113, removing the amorphous silicon film byirradiation with laser light or etching, and separating the elementformation layer 113; forming the separation layer 201 between thesubstrate 200 and the element formation layer 113, forming a metal oxidefilm between the separation layer 201 and the element formation layer113, embrittling the metal oxide film by crystallizing thereof, removinga part of the separation layer 201 by etching using a solution or ahalogen fluoride gas such as NF₃, BrF₃, ClF₃, and the like, andperforming the separation at the embrittled metal oxide film; andremoving the substrate 200 over which the element formation layer 113 isformed mechanically or by etching using a solution or a halogen fluoridegas such as NF₃, BrF₃, ClF₃, and the like. Alternatively, a method maybe used in which a film containing nitrogen, oxygen, or hydrogen (forexample, an amorphous silicon film containing hydrogen, an alloy filmcontaining hydrogen, or an alloy film containing oxygen) is used as theseparation layer 201, and the separation layer 201 is irradiated withlaser light to release the nitrogen, oxygen, or hydrogen contained inthe separation layer 201, thereby promoting separation between theelement formation layer 113 and the substrate 200.

When the above-described separation methods are combined, the transferstep can be conducted easily. For example, separation can be performedwith physical force (by a machine and the like) after performing: laserlight irradiation; etching to the separation layer 201 with a gas, asolution, or the like; and mechanical removal with a sharp knife,scalpel, or the like, so that the separation layer 201 and the elementformation layer 113 can be easily peeled off from each other.

Alternatively, separation of the element formation layer 113 from thesubstrate 200 may be carried out after penetrating a liquid into aninterface between the separation layer 201 and the element formationlayer 113.

Next, the element formation layer 113 which is separated from thesubstrate 200 to expose the separation layer 201 or the insulating layer112 is bonded to the plastic substrate 110 using a second adhesive 204which is different from the first adhesive 203 (see, FIG. 3C).

As the second adhesive 204, various curable adhesives such as a reactivecurable adhesive, a thermal curable adhesive, a photo curable adhesivesuch as an ultraviolet curable adhesive, an anaerobic adhesive, and thelike can be used.

As the plastic substrate 110, a variety of substrates having flexibilityand light-transmitting ability, a film of an organic resin, and the likecan be used. The plastic substrate 110 may be a structure bodycomprising a fibrous body and an organic resin. It is preferred to usethe structure body comprising the fibrous body and the organic resin asthe plastic substrate 110 since resistivity to the breaking caused bybending is improved, and thus, reliability is increased.

The structure body comprising the fibrous body and the organic resin canbe used as a film which can simultaneously function as the secondadhesive 204 and the plastic substrate 110. In this case, as the organicresin of the structure body, a resin such as a reactive curable resin, athermosetting resin, and a photo curable resin, and the like whosecuring is promoted by an additional treatment are preferably used.

After the bonding of the plastic substrate 110 to the element formationlayer 113, the provisional supporting substrate 202 is removed bydissolving or plasticizing the first adhesive 203. After the provisionalsupporting substrate 202 is removed, the first adhesive 203 is removedusing a solvent such as water to allow a surface of the first pixelelectrode 117 of the light-emitting element to be exposed (see, FIG.3D).

Through the above-mentioned process, the element formation layer 113,which comprises the color filter 116, the TFTs 114 and 115, the firstpixel electrode 117 of the light-emitting element, and the like, can bemanufactured over the plastic substrate 110.

After the surface of the first pixel electrode 117 is exposed, the ELlayer 119 is formed. A stacked structure of the EL layer 119 is notparticularly limited. A layer containing a substance having highelectron-transporting ability, a layer containing a substance havinghigh hole-transporting ability, a layer containing a substance havinghigh electron injection ability, a layer containing a substance havinghigh hole injection ability, a layer containing a bipolar substance (asubstance having high electron-transporting ability and high holetransporting ability), and the like are appropriately combined. Forexample, an appropriate combination of a hole injecting layer, ahole-transporting layer, a light-emitting layer, anelectron-transporting layer, an electron injection layer, and the likecan be performed. In this embodiment, a structure is explained in whichthe EL layer 119 comprises a hole injection layer, a hole-transportinglayer, a light-emitting layer, and an electron-transporting layer.Specific materials to form each of the layers are given below.

The hole injection layer is a layer that is provided in contact with ananode and contains a material with high hole injection ability.Specifically, molybdenum oxide, vanadium oxide, ruthenium oxide,tungsten oxide, manganese oxide, or the like can be used. Alternatively,the hole injection layer can be formed using any one of the followingmaterials: phthalocyanine compounds such as phthalocyanine (H₂PC) andcopper phthalocyanine (CuPc); aromatic amine compounds such as4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (DPAB) and4,4′-bis(N-{4-[N-(3-methylphenyl)-N-phenylamino]phenyl}-N-phenylamino)biphenyl(DNTPD); polymer compounds such aspoly(3,4-ethylenedioxythiophene)/poly(styrenesulfonic acid) (PEDOT/PSS);and the like.

Alternatively, as the hole injection layer, a composite materialcomprising a substance with high hole-transporting ability and anacceptor substance may be used. It is to be noted that, by using thecomposite material comprising the substance with high hole-transportingability and the acceptor substance, a material used to form an electrodemay be selected regardless of its work function. In other words, besidesa material with a high work function, a material with a low workfunction may also be used as the anode. As the acceptor substance,7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation:F₄-TCNQ), chloranil, and the like can be given. In addition, atransition metal oxide is given. In addition, oxides of metals thatbelong to Group 4 to Group 8 of the periodic table can be given.Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromiumoxide, molybdenum oxide, tungsten oxide, manganese oxide, and rheniumoxide are preferable because of a high electron accepting property.Among these metal oxides, molybdenum oxide is especially preferablesince it can be easily treated due to its stability in the air and lowhygroscopic property.

As the substance having high hole-transporting ability used for thecomposite material, any of various organic compounds such as an aromaticamine compound, a carbazole derivative, an aromatic hydrocarbon, and ahigh-molecular compound (such as an oligomer, a dendrimer, or a polymer)can be used. The organic compound used for the composite materialpreferably has a hole mobility of 10⁻⁶ cm²/Vs or higher is preferablyused. However, other materials than these materials may also be used aslong as hole-transporting ability is higher than electron-transportingability. The organic compound that can be used for the compositematerial is specifically shown below.

Examples of the aromatic amine compounds includeN,N′-di(p-tolyl)-N,N′-diphenyl-p-phenylenediamine (abbreviated toDTDPPA), 4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl(abbreviated to DPAB),4,4′-bis(N-{4-[N-(3-methylphenyl)-N-phenylamino]phenyl}-N-phenylamino)biphenyl(abbreviated to DNTPD),1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviatedto DPA3B), and the like.

Examples of a carbazole derivative include3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA1),3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA2),3-[N-(1-naphtyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole(abbreviation: PCzPCN1), 4,4′-di(N-carbazolyl)biphenyl (abbreviation:CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB),9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA),1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, and thelike.

Examples of the aromatic hydrocarbons include2-tert-butyl-9,10-di(2-naphthyl)anthracene (t-BuDNA),2-tert-butyl-9,10-di(1-naphthyl)anthracene,9,10-bis(3,5-diphenylphenyl)anthracene (DPPA),2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (t-BuDBA),9,10-di(2-naphthyl)anthracene (DNA), 9,10-diphenylanthracene (DPAnth),2-tert-butylanthracene (t-BuAnth),9,10-bis(4-methyl-1-naphthyl)anthracene (DMNA),2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene,9,10-bis[2-(1-naphthyl)phenyl]anthracene,2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene,2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9′-bianthryl,10,10′-diphenyl-9,9′-bianthryl,10,10′-bis(2-phenylphenyl)-9,9′-bianthryl,10,10′-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9′-bianthryl, anthracene,tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, andthe like. As well as these compounds, pentacene, coronene, or the likecan be used. Note that when a film of the above-mentioned aromatichydrocarbons is formed by an evaporation method, the number of thecarbon atoms participating in their condensed ring preferably rangesfrom 14 to 42 from the viewpoint of the evaporation behavior of thearomatic hydrocarbons and the quality of the formed film.

The aromatic hydrocarbon that can be used for the composite material mayhave a vinyl skeleton. As an aromatic hydrocarbon having a vinyl group,for example, 4,4′-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi),9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA),and the like are given.

The polymeric compounds are exemplified by poly(N-vinylcarbazole)(abbreviated to PVK), poly(4-vinyltriphenylamine) (abbreviated toPVTPA),poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamide] (abbreviated to PTPDMA),poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (abbreviated toPoly-TPD), and the like.

The hole-transporting layer is a layer that contains a substance withhigh hole-transporting ability. Examples of the substance having highhole-transporting ability include aromatic amine compounds such as4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbr.: NPB),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(abbr.: TPD), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (abbr.:TDATA), 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbr.: MTDATA),4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl (abbr.:BSPB), and the like. The materials described here are mainly substanceshaving hole mobility of 10⁻⁶ cm²/Vs or more. However, a material otherthan the above-described substances may be used as long as it has higherhole-transporting ability than electron-transporting ability. Note thatthe layer containing the substance with high hole-transporting abilityis not limited to a single layer, and two or more layers containing theaforementioned substances may be stacked.

Further, a high molecular compound such as poly(N-vinylcarbazole)(abbr.: PVK) or poly(4-vinyltriphenylamine) (abbr.: PVTPA) can also beused for the hole-transporting layer.

The light-emitting layer is a layer containing a light-emittingsubstance. The light-emitting layer may be a so-called single layerlight-emitting layer and a so-called host-guest type light-emittinglayer in which a light-emitting substance is dispersed in a hostmaterial, as long as the emission from the light-emitting layer islocated in the visible region. For example, followings are provided asthe light-emitting layer: a light-emitting layer containing alight-emitting substance having a broad emission spectrum (see, FIG.6A); a light-emitting layer containing a plurality of light-emittingsubstances having a different emission wavelength region (see, FIG. 6B);a light-emitting layer containing a plurality of layers which eachinclude a light-emitting substance with a different emission wavelengthregion (see, FIG. 6C); and the like. These structures may be combined toeach other. Note that in FIGS. 6A to 6C, a reference numeral 600represents the first pixel electrode of the light-emitting element; areference numeral 601 represents a second pixel electrode of thelight-emitting element; a reference numeral 602 represents the EL layer;reference numerals 603, 603-1, and 603-2 each represent thelight-emitting layer; and reference numerals 604, 604-1, and 604-2 eachrepresent the light-emitting substance.

In the case of the structures shown in FIGS. 6B and 6C, a combination ofthe light-emitting substances (corresponding to the light-emittingsubstances 604-1 and 604-2, but being not limited to two kinds ofsubstances) with different wavelength regions is generally exemplifiedby a combination of two kinds of light-emitting substances which emitlight of complementary colors to each other (for example, blue light andyellow light) or by a combination of three kinds of substances with red,blue and green emission colors.

In the case of the combination of two kinds of light-emitting substanceswith complementary emission colors in the structure shown in FIG. 6C, itis preferred to employ a structure in which, as shown in FIG. 7A, athree-layer structure containing a first light-emitting layer 603-1, asecond light-emitting layer 603-2, and a third light-emitting layer603-3 in that order from a side of the first pixel electrode 600 isprovided as the light-emitting layer 603; and a layer (the secondlight-emitting layer 603-2) containing a light-emitting substance 604-2capable of emitting light with a long wavelength is interposed betweenlayers (the first light-emitting layer 603-1 and the thirdlight-emitting layer 603-3) each containing a light-emitting substance604-1 capable of emitting light with a short wavelength. Note that, inthe structure of FIG. 7A, carrier-transporting ability of each of thelight-emitting layers is tuned by appropriately selecting host materialsto allow recombination of electrons and holes to occur in the vicinityof an interface of the layer (the second light-emitting layer 603-2)containing the light-emitting substance 604-2 which is located on theside of the second pixel electrode 601 (i.e., an interface between thesecond light-emitting layer 603-2 and the third light-emitting layer603-3). By using such structure, the lifetime of the light-emittingelement can be improved, and the emission from the light-emittingsubstance capable of emitting light with the long wavelength and thatfrom the light-emitting substance capable of emitting light with theshort wavelength can be readily balanced.

Here, in the case where the first pixel electrode 600 and the secondpixel electrode 601 are used as the anode and the cathode, respectively,“recombination of holes and electrons in the vicinity of an interface ofthe layer, containing the light-emitting substance capable of emittinglight with the long wavelength, the interface of which is located on theside of the second pixel electrode, by tuning carrier transportingability of each of the light-emitting layers through the appropriateselection of the host materials” can be achieved by designing thelight-emitting element so that the layer (the third light-emitting layer603-3), which is located on the side of second pixel electrode 601 andcontains the light-emitting substance 604-1 capable of emitting lightwith short wavelength, has electron-transporting ability and the layer(the first light-emitting layer 603-1), which is located on the anodeside and contains the light-emitting substance 604-1 capable of emittinglight with the short wavelength, and the layer (the secondlight-emitting layer 603-2), which contains the light-emitting substance604-2 capable of emitting light with the long wavelength, havehole-transporting ability. When the first pixel electrode 600 and thesecond pixel electrode 601 are used as the cathode and the anode,respectively, the combination concerning the carrier-transportingability is reversed.

As a result, electrons, which cannot participate to recombination in thevicinity of the cathode side interface (the interface between the secondlight-emitting layer 603-2 and the third light-emitting layer 603-3) ofthe layer (the second light-emitting layer 603-2) containing thelight-emitting substance capable of emitting light with the longwavelength, are provided with an opportunity to undergo recombination inthe layer (the first light-emitting layer 603-1) which is located on theanode side and contains the light-emitting substance capable of emittinglight with the short wavelength. Thus, deterioration resulting from aphenomenon that a carrier (electron or hole) reaches to acarrier-transporting layer which has carrier-transporting abilityopposite to the respective carrier can be retarded, which contributes toimprovement in lifetime of the light-emitting element.

Energy obtained by recombination of holes and electrons is readilytransferred from a substance which emits light with a short wavelengthto a substance which emits light with a long wavelength. In such a case,light emitted from the substance which emits light with the longwavelength is enhanced, which makes it difficult to balance theintensities of emissions from the substance which emits light with theshort wavelength and from the substance which emits light with the longwavelength. However, by using the above-mentioned structure, theelectron which fails to participate to recombination in the vicinity ofthe interface between the second light-emitting layer 603-2 and thethird light-emitting layer 603-3 can be subjected to recombination inthe layer (the first light-emitting layer 603-1) which is located on theanode side and contains the light-emitting substance capable of emittinglight with the short wavelength. Thus, a well balanced emission isattainable, and an emission with desired color can be obtained.

In such a structure, when an anthracene derivative, which haselectron-transporting ability as well as hole-transporting ability, isused as a host material of the first light-emitting layer 603-1 and thesecond light-emitting layer 603-2 in which a light-emitting substance isdispersed, the effect of improving the lifetime is more effectivelyobtained.

When three kinds of light-emitting substances, i.e., red, blue, andgreen-emissive light-emitting substances, are combined in the structureshown in FIG. 6C, it is preferred, as shown in FIG. 7B, to employ astructure in which a light-emitting layer 603 is formed as a four-layerstructure containing, from the side of the first pixel electrode 600, afirst light-emitting layer 603-1, a second light-emitting layer 603-2, athird light-emitting layer 603-3, and a fourth light-emitting layer603-4 and in which the layer (the third light-emitting layer 603-3)containing a green-emissive light-emitting substance 604-7 and the layer(the second light-emitting layer 603-2) containing a red-emissivelight-emitting substance 604-6 are sandwiched between the layers (thefirst light-emitting layer 603-1 and the fourth light-emitting layer603-4) containing a blue-emissive light-emitting substance 604-5. Notethat, in the structure shown in FIG. 7B, carrier-transporting ability ofeach of the light-emitting layers is tuned to allow the region forrecombination of holes and electrons to be located in the vicinity ofthe interface between the cathode-side layer (the fourth light-emittinglayer 603-4) containing the blue-emissive light-emitting substance 604-5and the layer (the third light-emitting layer 603-3) containing thegreen-emissive light-emitting substance 604-7. By using such structure,the lifetime of the light-emitting element can be improved, and theemission from the light-emitting substance capable of emitting lightwith the long wavelength and that from the light-emitting substancecapable of emitting light with the short wavelength can be readilybalanced.

Note that, when the first pixel electrode 600 and the second pixelelectrode 601 are respectively the anode and cathode, recombination inthe vicinity of the interface between the fourth light-emitting layer603-4 and the third light-emitting layer 603-3 can be achieved bydesigning the light-emitting element so that: the cathode-side layer(the fourth light-emitting layer 603-4) containing the blue-emissivelight-emitting substance 604-5 has electron-transporting ability; andthe layer (the third light-emitting layer 603-3) containing thegreen-emissive light-emitting substance 604-7, the layer (the secondlight-emitting layer 603-2) containing the red-emissive light-emittingsubstance 604-6, and the anode-side layer (the first light-emittinglayer 603-1) containing the blue-emissive light-emitting substance 604-5have hole-transporting ability. When the first pixel electrode 600 andthe second pixel electrode 601 are the cathode and the anode,respectively, the carrier-transporting ability of each layer isreversed. Note that carrier-transporting ability of each of thelight-emitting layers can be determined by carrier-transporting abilityof the substance which is contained at the highest composition in thecorresponding light-emitting layers.

As a result, electrons, which cannot participate to recombination in thevicinity of the interface between the cathode-side layer (the fourthlight-emitting layer 603-4) containing the blue-emissive light-emittingsubstance 604-5 and the layer (the third light-emitting layer 603-3)containing the green-emissive light-emitting substance 604-7, areprovided with an opportunity to undergo recombination in the anode-sidelayer (the first light-emitting layer 603-1) containing theblue-emissive light-emitting substance 604-5. Thus, deteriorationresulting from a phenomenon that a carrier (electron or hole) reaches toa carrier-transporting layer which has carrier-transporting abilityopposite to the respective carrier can be retarded, which contributes toimprovement in lifetime of the light-emitting element.

Energy obtained by recombination of holes and electrons is readilytransferred from a substance which emits light with a short wavelengthto a substance which emits light with a long wavelength. In such a case,light emitted from the substance which emits light with the longwavelength is enhanced, which makes it difficult to balance theintensities of emissions from the substance which emits light with theshort wavelength and from the substance which emits light with the longwavelength. However, by using the above-mentioned structure, theelectron which once fails to participate to recombination is subjectedto recombination in the anode-side layer (the first light-emitting layer603-1) containing the blue-emissive light-emitting substance 604-5,giving an emission of light with the short wavelength. Thus, awell-balanced emission is attainable, and an emission with desired colorcan be obtained.

The light-emitting substance used is not particularly limited, and knownfluorescent substances or phosphorescent substances can be used. Asfluorescent substances, for example, in addition toN,N′-bis[4-(9H-carbazol-9-yl)phenyl]-N,N′-diphenylstilbene-4,4′-diamine(abbreviation: YGA2S) and4-(9H-carbazol-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine(abbreviation: YGAPA), and the like, there are fluorescent substanceswith an emission peak equal to or greater than 450 nm, such as4-(9H-carbazol-9-yl)-4′-(9,10-diphenyl-2-anthryl)triphenylamine(abbreviation: 2YGAPPA),N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene(abbreviation: TBP),4-(10-phenyl-9-anthryl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBAPA),N,N″-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N′,N′-triphenyl-1,4-phenylenediamine](abbreviation: DPABPA),N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: 2PCAPPA),N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPAPPA),N,N,N′,N′,N″,N″,N′″,N′″-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine(abbreviation: DBC1), coumarin 30,N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA),N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCABPhA),N-(9,10-diphenyl-2-anthryl)-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPAPA),N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPABPhA),9,10-bis(1,1′-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine(abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine(abbreviation: DPhAPhA), coumarin 545T, N,N′-diphenylquinacridone(abbreviation: DPQd), rubrene,5,12-bis(1,1′-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT),2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1),2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2),N,N,N′,N′-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation:p-mPhTD),7,13-diphenyl-N,N,N′,N′-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD),2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: DCJTI),2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: DCJTB),2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile(abbreviation: BisDCM), and2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: BisDCJTM). As phosphorescent substances, for example, inaddition tobis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III)tetrakis(1-pyrazolyl)borate(abbreviation: FIr6), there are phosphorescent substances with anemission wavelength in the range of 470 nm to 500 nm, such asbis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III)picolinate(abbreviation: FIrpic),bis[2-(3′,5′bistrifluoromethylphenyl)pyridinato-N,C^(2′)]iridium(III)picolinate(abbreviation: Ir(CF₃ppy)₂(pic)), andbis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III)acetylacetonate(abbreviation: FIracac); phosphorescent materials with an emissionwavelength equal to or greater than 500 nm (materials which emit greenlight), such as tris(2-phenylpyridinato)iridium(III) (abbreviation:Ir(Ppy)₃), bis(2-phenylpyridinato)iridium(III)acetylacetonate(abbreviation: Ir(ppy)₂(acac)),bis(1,2-diphenyl-1H-benzimidazolato)iridium(III)acetylacetonate(abbreviation: Ir(pbi)₂(acac)),tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation:Tb(acac)₃(Phen)), bis(benzo[h]quinolinato)iridium(III)acetylacetonate(abbreviation: Ir(bzq)₂(acac)),bis(2,4-diphenyl-1,3-oxazolato-N,C^(2′))iridium(III)acetylacetonate(abbreviation: Ir(dpo)₂(acac)),bis[2-(4′-perfluorophenylphenyl)pyridinato]iridium(III)acetylacetonate(abbreviation: Ir(p-PF-ph)₂(acac)),bis(2-phenylbenzothiazolato-N,C^(2′))iridium(III)acetylacetonate(abbreviation: Ir(bt)₂(acac)),bis[2-(2′-benzo[4,5-α]thienyl)pyridinato-N,C^(3′)]iridium(III)acetylacetonate(abbreviation: Ir(btp)₂(acac)),bis(1-phenylisoquinolinato-N,C^(2′))iridium(III)acetylacetonate(abbreviation: Ir(piq)₂(acac)),(acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)(abbreviation: Ir(Fdpq)₂(acac)),(acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III)(abbreviation: Ir(tppr)₂(acac)),2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinatoplatinum(II)(abbreviation: PtOEP),tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III)(abbreviation: Eu(DBM)₃(Phen)), andtris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III)(abbreviation: Eu(TTA)₃(Phen)). The light-emitting substances can beselected from the above-mentioned materials or other known materials inconsideration of emission colors (or peak wavelengths of an emission) ofeach of the light-emitting layers.

When the host material is used, the following can be given: metalcomplexes such as tris(8-quinolinolato)aluminum(III) (abbreviation:Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq₃),bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq₂),bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III)(abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq),bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), andbis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ);heterocyclic compounds such as2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene(abbreviation: OXD-7),3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole(abbreviation: TAZ),2,2′,2″-(1,3,5-benzenetriyl)-tris(1-phenyl-1H-benzimidazole)(abbreviation: TPBI), bathophenanthroline (abbreviation: BPhen),bathocuproine (abbreviation: BCP), and9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation:CO11); and aromatic amine compounds such as NPB (or α-NPD), TPD, andBSPB. In addition, condensed polycyclic aromatic compounds such asanthracene derivatives, phenanthrene derivatives, pyrene derivatives,chrysene derivatives, and dibenzo[g,p]chrysene derivatives are given.The following is specifically given as the condensed polycyclic aromaticcompound: 9,10-diphenylanthracene (DPAnth);N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(CzA1PA); 4-(10-phenyl-9-anthryl)triphenylamine (DPhPA);4-(9H-carbazol-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine (YGAPA);N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(PCAPA);N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine(PCAPBA); N-9-diphenyl-N-(9,10-diphenyl-2-anthryl)-9H-carbazol-3-amine(2PCAPA); 6,12-dimethoxy-5,11-diphenylchrysene,N,N,N′,N′,N″,N″,N′″,N′″-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetramine(DBC1); 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (CzPA);3,6-diphenyl-9-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazole (DPCzPA),9,10-bis(3,5-diphenylphenyl)anthracene (DPPA),9,10-di(2-naphthyl)anthracene (DNA),2-tert-butyl-9,10-di(2-naphthyl)anthracene (t-BuDNA), 9,9′-bianthryl(BANT), 9,9′-(stilbene-3,3′-diyl)diphenanthrene (DPNS),9,9′-(stilbene-4,4′-diyl)diphenanthrene (DPNS2),3,3′,3″-(benzene-1,3,5-triyl)tripyrene (TPB3) and the like. From thesesubstances or other known substances, the host material may be selectedso that the host material has a larger energy gap (or a triplet energyif the light-emitting substance emits phosphorescence) than thelight-emitting substance dispersed in the light-emitting layer and hascarrier-transporting ability required for each of the light-emittinglayers.

The electron-transporting layer is a layer that contains a substancewith high electron-transporting ability. For example, a layer containinga metal complex having a quinoline skeleton or a benzoquinolineskeleton, such as tris(8-quinolinolato)aluminum (abbreviation: Alq),tris(4-methyl-8-quinolinolato)aluminum (abbreviation: Almq₃),bis(10-hydroxybenzo[h]-quinolinato)beryllium (abbreviation: BeBq₂), orbis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum (abbreviation:BAlq) can be used. Alternatively, a metal complex having anoxazole-based or thiazole-based ligand, such asbis[2-(2-hydroxyphenyl)benzoxazolato]zinc (abbreviation: Zn(BOX)₂) orbis[2-(2-hydroxyphenyl)-benzothiazolato]zinc (abbreviation: Zn(BTZ)₂)can be used. Besides the metal complexes,2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene(abbreviation: OXD-7),3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole(abbreviation: TAZ), bathophenanthroline (abbreviation: BPhen),bathocuproine (abbreviation: BCP), or the like can also be used. Thesubstances described here are mainly those having electron mobility of10⁻⁶ cm²/Vs or more. It is to be noted that a substance other than theabove substances may be used as long as it has higherelectron-transporting ability than hole transporting ability.

Further, the electron-transporting layer may be formed as not only asingle layer but also as a stacked layer in which two or more layersformed using the above mentioned substances are stacked.

Further, a layer for controlling transport of electron may be providedbetween the electron-transporting layer and the light-emitting layer.Note that the layer for controlling transport of electron is a layer inwhich a small amount of a substance having high electron-trappingability is added to a layer containing the above-mentioned substanceshaving high electron-transporting ability. The layer for controllingtransport of electron controls transport of electron, which enablesadjustment of carrier balance. Such a structure is very effective insuppressing a problem (such as shortening of element lifetime) caused bya phenomenon that electron passes through the light-emitting layer.

Further, an electron injection layer may be provided so as to be incontact with an electrode functioning as a cathode. As the electroninjection layer, alkali metal, alkaline earth metal, or a compound ofthereof such as lithium fluoride (LiF), cesium fluoride (CsF), calciumfluoride (CaF₂), and the like can be employed. For example, a layerwhich contains both a substance having electron-transporting ability andan alkali metal, an alkaline earth metal, or a compound thereof (a layerof Alq including magnesium (Mg) for example) can be used. Note thatelectron can be efficiently injected from the cathode by using, as theelectron injection layer, a substance having electron-transportingability to which an alkali metal or an alkaline earth metal is mixed.

When the second pixel electrode 601 is used as the cathode, a metal, analloy, an electrically conductive compound, a mixture thereof, or thelike having a low work function (specifically, work function of smallerthan or equal to 3.8 eV), can be used as a substance for the secondpixel electrode 601. As a specific example of such a cathode material,an element belonging to Group 1 or Group 2 in the periodic table, i.e.,an alkali metal such as lithium (Li) or cesium (Cs), or an alkalineearth metal such as magnesium (Mg), calcium (Ca), or strontium (Sr); analloy containing any of these metals (such as MgAg or AlLi); a rareearth metal such as europium (Eu) or ytterbium (Yb); an alloy containingsuch a rare earth metal; or the like can be used. However, when theelectron injection layer is provided between the cathode and theelectron-transporting layer, any of a variety of conductive materialssuch as Al, Ag, ITO, and indium oxide-tin oxide containing silicon orsilicon oxide, and the like can be used regardless of its work functionas the cathode. Films of these electrically conductive materials can beformed by a sputtering method, an ink-jet method, a spin coating method,or the like.

It is preferable that, when the second pixel electrode 601 is used asthe anode, the second pixel electrode 601 is formed using a metal, analloy, or a conductive compound, a mixture thereof, or the like having ahigh work function (specifically greater than or equal to 4.0 eV).Specifically, an example thereof is indium oxide-tin oxide (ITO: indiumtin oxide), indium oxide-tin oxide containing silicon or silicon oxide,indium oxide-zinc oxide (IZO: indium zinc oxide), indium oxidecontaining tungsten oxide and zinc oxide (IWZO), or the like. Suchconductive metal oxide films are usually formed by a sputtering method,but may also be formed by using a sol-gel method or the like. Forexample, indium zinc oxide (IZO) can be formed by a sputtering methodusing a target in which 1 to 20 wt % of zinc oxide is added to indiumoxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) canbe formed by a sputtering method using a target in which 0.5 wt % to 5wt % of tungsten oxide and 0.1 wt % to 1 wt % of zinc oxide arecontained in indium oxide. In addition, gold (Au), platinum (Pt), nickel(Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt(Co), copper (Cu), palladium (Pd), a nitride of a metal (such astitanium nitride), or the like can be given. By forming theabove-mentioned composite material so as to be in contact with theanode, a material for the anode can be selected regardless the magnitudeof its work function.

Note that, as to the above-mentioned EL layer, a plurality of EL layermay be formed between the first pixel electrode 600 and the second pixelelectrode 601 as shown in FIG. 8. In this case, a charge generationlayer 803 is preferably provided between the stacked EL layers 800 and801. The charge generation layer 803 can be formed by using theabove-mentioned composite material. Further, the charge generation layer803 may have a stacked structure comprising a layer containing thecomposite material and a layer containing another material. In thiscase, as the layer containing another material, a layer containing anelectron donating substance and a substance with highelectron-transporting ability, a layer comprising a transparentconductive material, and the like can be used. Such a structure allowsthe formation of a light-emitting element with high emission efficiencyand a long lifetime. Moreover, a light-emitting element which provides aphosphorescent emission from one of the EL layers and a fluorescentemission from the other of the EL layers can be readily obtained. Notethat this structure can be combined with the above-mentioned structuresof the EL layer. For instance, the EL layer having the structure of FIG.6C and the EL layer having the structure of FIG. 6A can be stacked.Specifically, it is readily achieved to obtain blue and greenfluorescent emissions from the EL layer 800 having the structure of FIG.6C and simultaneously obtain a red phosphorescent emission from the ELlayer 801 having the structure of FIG. 6A, where the charge generationlayer 803 is sandwiched therebetween. In a similar way, green and redphosphorescent emissions are obtained from the EL layer 800 having thestructure of FIG. 6C, and a blue fluorescent emission is simultaneouslyobtained from the EL layer 801 having the structure of FIG. 6A, wherethe charge generation layer 803 is sandwiched therebetween. Inparticular, the structure which provides the green and redphosphorescent emissions and the blue fluorescent emission is preferredsince a white emission with well-balanced emission efficiencies of theEL layers is attainable.

Through the above-mentioned process, the light-emitting devices shown inFIGS. 1A to 1C can be obtained.

After the formation of the element formation layer and thelight-emitting layer, it is preferred to seal the light-emitting elementwith an organic resin 400, a protective film 401, and the like as shownin FIGS. 4A and 4B in order to prevent a substance which promotesdeterioration of the EL layer from entering from the outside. A sealingsubstrate may be used instead of the organic resin 400 and theprotective film 401. However, the protective film 401 is not necessarilyformed over input and output terminals which are connected to an FPC andthe like later.

Since the light-emitting device of the present embodiment displays animage toward the plastic substrate 110 side through the color filter, itis possible to use the above-mentioned organic resin 400, the protectivefilm 401, and the sealing substrate even if they are colored or have lowtransmissivity with respect to visible light. In the case where theorganic resin 400, the protective film 401, and the sealing substrateeach are formed using light-transmitting materials, a monochromic imagecan be also supplied from the sealing substrate side if the second pixelelectrode is formed by a light-transmitting material or in a shape whichallows visible light to be transmitted therethrough. A material similarto that for the plastic substrate 110 can be used for the sealingsubstrate.

Next, the FPC 402 is bonded to each of electrodes of the input andoutput terminals with an anisotropic conductive material. An IC chip maybe mounted thereover if necessary.

By the above-mentioned process, manufacture of a module of thelight-emitting device to which the FPC 402 is connected is completed.

Note that, in the case where the semiconductor layer of the TFT includedin the light-emitting device of the present embodiment is not subjectedto treatment performed at a high-temperature or a laser irradiation, astructure shown in FIG. 2 can be employed.

In the structure shown in FIG. 2, an adhesive 111 is provided over aplastic substrate 110 and bonds an element formation layer formed over afirst insulating layer 112 to the plastic substrate 110. A color filter300 is provided over the first insulating layer 112, and a TFT 302 isprovided while a second insulating layer 301 formed over the colorfilter 300 is sandwiched between the color filter 300 and the TFT 302.The second insulating layer 301 can be formed by using an inorganicinsulating material such as silicon oxide, silicon oxynitride, siliconnitride, silicon nitride oxide, and the like or an organic insulatingmaterial such as an acrylic, a polyimide, and the like. The use of theorganic insulating material is preferred since the organic insulatingmaterial can reduce a step caused by formation of the color filter 300.Furthermore, it is preferred to provide a protective insulating filmover the second insulating layer 301 in order to suppress an adverseinfluence of contaminant, such as a gas released from the color filter300, upon the TFT 302. The protective insulating film is preferablyformed using an inorganic insulating material such as silicon oxide,silicon oxynitride, silicon nitride, silicon nitride oxide, and thelike. In particular, it is preferred to use silicon nitride or siliconnitride oxide which has a composition of nitrogen higher than that ofoxygen. Note that the protective insulating film is not necessarilyprovided in the case where the second insulating layer 301 is formed byan inorganic insulating film.

As shown in FIGS. 1A to 1C, after a separation layer and the firstinsulating layer 112 are formed, the color filter 300 and the secondinsulating layer 301 are formed over a substrate with low flexibility,which is followed by the formation of the TFT 302. The TFT 302 may havea known structure and be formed by a known method which does not requirehigh temperature treatment. For instance, a TFT having a semiconductorsuch as the above-mentioned microcrystalline semiconductor, theamorphous semiconductor, the oxide semiconductor, the semiconductorcontaining an organic material as a main component, and the like isexemplified. After forming the TFT 302, a first pixel electrode 303 of alight-emitting element and a partition layer 304 are formed. Then, theseparation is carried out in a similar manner to that mentioned above toachieve the transfer to a plastic substrate 110, leading to theformation of a light-emitting device similarly to that shown in FIGS. 1Ato 1C.

In the light-emitting device with such a structure, the secondinsulating layer 301 is singly able to suppress adverse influence of acontaminant from the color filter 300 upon the TFT 302 and thelight-emitting element, which contributes to reduction of manufacturingprocess.

It should be noted that even in the structure shown in FIG. 2, the colorfilter is formed using the substrate with low flexibility. Therefore,similarly to the structure shown in FIGS. 1A to 1C, the light-emittingdevice with the structure of FIG. 2 can display a full color image withhigh resolution in spite of its flexibility.

Embodiment 2

A top view and a sectional view of a module of a light-emitting device(also referred to as an EL module) are illustrated in FIGS. 4A and 4B,respectively.

FIG. 4A is a top view showing the EL module, and FIG. 4B is a viewshowing a part of a cross section taken along line A-A′ of FIG. 4A. InFIG. 4A, an insulating layer 501 is formed over a plastic substrate 110with an adhesive 500 (for example, the second adhesive and the like)sandwiched therebetween, over which a pixel portion 502, a source sidedriving circuit 504, and a gate side driving circuit 503 are formed.These elements can be obtained by the manufacturing method demonstratedin embodiment 1.

Reference numerals 400 and 401 denote an organic resin and a protectivefilm, respectively, and the pixel portion 502, the source side drivingcircuit 504, and the gate side driving circuit 503 are covered by theorganic resin 400 which is further covered by the protective film 401.Sealing by a cover material can be further conducted by using anadhesive. The cover material can be bonded as a supporting base beforethe separation process.

A reference numeral 508 denotes a wiring for transmitting signalsinputted to the source side driver circuit 504 and the gate side drivercircuit 503 and receives video signals, clock signals, and the like froman FPC (Flexible Printed Circuit) 402 which functions as an externalinput terminal. Although only the FPC 402 is depicted in FIGS. 4A and4B, a printed wiring board (PWB) may be provided to the FPC 402. Thelight-emitting device according to the embodiments of the inventionincludes not only a light-emitting device itself but also a state inwhich an FPC or a PWB is attached thereto.

Next, a sectional structure is described with reference to FIG. 4B. Theinsulating layer 501 is provided over and in contact with the adhesive500, and the pixel portion 502 and the gate side driving circuit 503 areformed over the insulating layer 501. The pixel portion 502 comprises aplurality of pixels 515, and the plurality of pixels 515 include acurrent control TFT 511 and a first pixel electrode 512 which iselectrically connected to one of source and drain electrodes of thecurrent control TFT 511. Although FIG. 4B shows only one of theplurality of pixels 515, they are arranged in a matrix form in the pixelportion 502. The gate side driver circuit 503 is formed using a CMOScircuit in which a plurality of n-channel TFTs 513 and a plurality ofp-channel TFTs 514 are combined.

Embodiment 3

In this embodiment, electronic devices which include the light-emittingdevices described in embodiments 1 and 2 are described.

Examples of the electronic devices which include the light-emittingdevices described in embodiments 1 or 2 include cameras such as videocameras and digital cameras, goggle type displays, navigation systems,audio playback devices (e.g., car audio systems and audio systems),computers, game machines, portable information terminals (e.g., mobilecomputers, mobile phones, portable game machines, and electronic books),image playback devices in which a recording medium is provided(specifically, devices that are capable of playing back recording mediasuch as digital versatile discs (DVDs) and equipped with a display unitthat can display images), and the like. Specific examples of suchelectronic devices are shown in FIGS. 5A to 5D.

FIG. 5A illustrates a television device which includes a housing 9101, asupporting base 9102, a display portion 9103, speaker portions 9104,video input terminals 9105, and the like. The television device ismanufactured by using the light-emitting device shown in embodiment 1 or2 in the display portion 9103. The television device, in which theflexible light-emitting device capable of displaying a full color imagewith high resolution is mounted, allows the display portion 9103 topossess a curved shape, is lightweight, and supplies an image with highquality.

FIG. 5B illustrates a computer which includes a main body 9201, ahousing 9202, a display portion 9203, a keyboard 9204, an externalconnection port 9205, a pointing device 9206, and the like. The computeris manufactured by using the light-emitting device shown in embodiment 1or 2 in the display portion 9203. The computer, in which the flexiblelight-emitting device capable of displaying a full color image with highresolution is mounted, allows the display portion 9203 to possess acurved shape, is lightweight, and supplies an image with high quality.

FIG. 5C illustrates a mobile phone, which includes a main body 9401, ahousing 9402, a display portion 9403, an audio input portion 9404, anaudio output portion 9405, operation keys 9406, an external connectionport 9407, an antenna 9408, and the like. The mobile phone ismanufactured by using the light-emitting device shown in embodiment 1 or2 in the display portion 9403. The mobile phone, in which the flexiblelight-emitting device capable of displaying a full color image with highresolution is mounted, allows the display portion 9403 to possess acurved shape, is lightweight, and supplies an image with high quality.In addition, the lightweight mobile phone can have appropriate weighteven if a variety of additional values are added thereto, and thus themobile phone is suitable as a highly functional mobile phone.

FIG. 5D illustrates a camera which includes a main body 9501, a displayportion 9502, a housing 9503, an external connecting port 9504, a remotecontrol receiving portion 9505, an image receiving portion 9506, abattery 9507, an audio input portion 9508, operation keys 9509, aneyepiece portion 9510, and the like. The camera is manufactured by usingthe light-emitting device shown in embodiment 1 or 2 in the displayportion 9502. The camera, in which the flexible light-emitting devicecapable of displaying a full color image with high resolution ismounted, allows the display portion 9502 to possess a curved shape, islightweight, and supplies an image with high quality.

FIG. 5E illustrates a flexible display which includes a main body 9601,a display portion 9602, an insert portion of an external memory 9603, aspeaker portion 9604, operation keys 9605, and the like. A televisionreceiving antenna, an external input, an external output terminal, abattery, and the like may be mounted on the main body 9601. The flexibledisplay is manufactured by using the light-emitting device shown inembodiment 1 or 2 in the display portion 9602. The display portion 9602can possess a curved shape, is lightweight, and supplies an image withhigh quality. When the display portions of the electronic devices shownin FIGS. 5A to 5D are manufactured so as to have a curved shape and theflexible display shown in FIG. 5E is mounted on the display portions, aelectronic device having a display portion with a curved shape can besupplied.

As described above, the range of application of the light-emittingdevice manufactured by using the light-emitting element shown inembodiment 1 or 2 is extremely wide, and the light-emitting device canbe applied to electronic devices in a wide variety of fields.

This application is based on Japanese Patent Application serial no.2008-180229 filed with Japan Patent Office on Jul. 10, 2008, the entirecontents of which are hereby incorporated by reference.

EXPLANATION OF REFERENCE

-   110: plastic substrate, 111: adhesive, 112: insulating layer, 113:    element formation layer, 114: TFT, 115: TFT of driving circuit    portion, 116: color filter, 117: first pixel electrode, 118:    partition layer, 119: EL layer, 120: second pixel electrode, 121:    light-emitting element, 122: first protective insulating film, 123:    second protective insulating film, 124: color filter, 200:    substrate, 201: separation layer, 202: provisional supporting    substrate, 203: first adhesive, 204: second adhesive, 300: color    filter, 301: second insulating layer, 302: TFT, 303, first pixel    electrode, 304: partition layer, 400: organic resin, 401: protection    film, 402: FPC, 500: adhesive, 501: insulating layer, 502: pixel    portion, 503: gate side driving circuit, 504: source side driving    circuit, 508: wiring, 511: current control TFT, 512, first pixel    electrode, 513: n-channel TFT, 514: p-channel TFT, 600: first pixel    electrode, 601: second pixel electrode, 602: EL layer, 603:    light-emitting layer, 603-1: first light-emitting layer, 603-2:    second light-emitting layer, 603-3: third light-emitting layer,    603-4, fourth light-emitting layer, 604: light-emitting substance,    604-1: light-emitting substance, 604-2: light-emitting substance,    604-5: blue-emissive light-emitting substance, 604-6: red-emissive    light-emitting substance, 604-7: green-emissive light-emitting    substance, 800: EL layer, 801: EL layer, 803: charge generation    layer, 9101: housing, 9102: supporting base, 9103: display portion,    9104: speaker portion, 9105: video input terminal, 9201: main body,    9202: supporting base, 9203: display portion, 9204: keyboard, 9205:    external connection port, 9206: pointing device, 9401: main body,    9402: housing, 9403: display portion, 9404: audio input portion,    9405: audio output portion, 9406: operation key, 9407: external    connection port, 9408: antenna, 9501: main body, 9502: display    portion, 9503: housing, 9504: external connecting port, 9505: remote    control receiving portion, 9506: image receiving portion, 9507:    battery, 9508: audio input portion, 9509: operation key, 9510:    eyepiece portion, 9601: main body, 9602: display portion, 9603:    insert portion of external memory, 9604: speaker portion, 9605:    operation key.

The invention claimed is:
 1. A manufacturing method of a light-emittingdevice, the manufacturing method comprising the steps of: forming anelement formation layer over a first substrate, wherein the elementformation layer is formed by a method comprising the steps of: forming athin film transistor over the first substrate; forming a firstinsulating film over the thin film transistor; forming a color filterover the first insulating film; forming an interlayer insulating filmover the color filter; and forming a first electrode havinglight-transmitting ability over the interlayer insulating film, whereinthe first electrode is electrically connected to the thin filmtransistor; bonding the element formation layer with a second substrate,allowing the element formation layer to be sandwiched between the firstsubstrate and the second substrate; separating the first substrate fromthe element formation layer; bonding the element formation layer with athird substrate, allowing the element formation layer to be sandwichedbetween the second substrate and the third substrate; separating thesecond substrate from the element formation layer; forming an EL layerover the first electrode; and forming a second electrode over the ELlayer, wherein the third substrate is a plastic substrate havinglight-transmitting ability.
 2. The manufacturing method according toclaim 1, wherein the plastic substrate is an organic resin.
 3. Themanufacturing method according to claim 1, wherein the plastic substratecomprises a fibrous body and an organic resin.
 4. The manufacturingmethod according to claim 1, wherein the first substrate is selectedfrom a glass substrate, a quartz substrate, a sapphire substrate, aceramic substrate, and a metal substrate having an insulating surface.5. The manufacturing method according to claim 1, further comprising thestep of sealing the element formation layer.
 6. The manufacturing methodaccording to claim 1, wherein the EL layer emits light with white color.7. The manufacturing method according to claim 1, further comprising thestep of forming a separation layer over the first substrate over whichthe element formation layer is formed.
 8. The manufacturing methodaccording to claim 1, wherein the formation of the EL layer is performedafter separating the second substrate from the element formation layerand the third substrate.
 9. The manufacturing method according to claim1, wherein the method for forming the element formation layer furthercomprises a step of forming a second insulating film over the colorfilter over which the interlayer insulating film is formed.
 10. Themanufacturing method according to claim 1, wherein the method forforming the element formation layer further comprises a step of forminga second insulating film over the color filter over which the interlayerinsulating film is formed, wherein the first insulating film and thesecond insulating film each are in contact with the color filter, andwherein the first insulating film and the second insulating film are incontact with each other in a region where the thin film transistor isformed.
 11. A manufacturing method of a light-emitting device, themanufacturing method comprising the steps of: forming a color filterover a first substrate; forming a first insulating layer over the firstsubstrate; forming an element formation layer over the first insulatinglayer, wherein the element formation layer is formed by a methodcomprising the steps of: forming a thin film transistor over the firstinsulating layer; forming an interlayer insulating film over the thinfilm transistor; forming a first electrode having light-transmittingability over the interlayer insulating film, wherein the first electrodeis electrically connected to the thin film transistor; bonding theelement formation layer with a second substrate, allowing the elementformation layer to be sandwiched between the first substrate and thesecond substrate; separating the first substrate from the color filter;bonding the element formation layer with a third substrate, allowing thecolor filter, the first insulating layer, and the element formationlayer to be sandwiched between the second substrate and the thirdsubstrate; separating the second substrate from the element formationlayer; forming an EL layer over the first electrode; and forming asecond electrode over the EL layer, wherein the third substrate is aplastic substrate having light-transmitting ability.
 12. Themanufacturing method according to claim 11, wherein the plasticsubstrate is an organic resin.
 13. The manufacturing method according toclaim 11, wherein the plastic substrate comprises a fibrous body and anorganic resin.
 14. The manufacturing method according to claim 11,wherein the first substrate is selected from a glass substrate, a quartzsubstrate, a sapphire substrate, a ceramic substrate, and a metalsubstrate having an insulating surface.
 15. The manufacturing methodaccording to claim 11, further comprising the step of sealing theelement formation layer.
 16. The manufacturing method according to claim11, wherein the EL layer emits light with white color.
 17. Themanufacturing method according to claim 11, further comprising the stepof forming a separation layer between the first substrate and the colorfilter.
 18. The manufacturing method according to claim 11, wherein theformation of the EL layer is performed after separating the secondsubstrate from the element formation layer and the third substrate. 19.A light-emitting device comprising: a flexible substrate havinglight-transmitting ability; a thin film transistor over the flexiblesubstrate with an adhesive provided therebetween; a first insulatingfilm over the thin film transistor; a color filter over the firstinsulating film; a light-emitting element over the color filter andcomprising: a first electrode having light-transmitting ability andbeing electrically connected to the thin film transistor; an EL layerover the first electrode; and a second electrode over the EL layer; anda protective film over the light-emitting element, wherein the thin filmtransistor is overlapped with the color filter, and wherein the thinfilm transistor comprises an oxide semiconductor layer.
 20. Thelight-emitting device according to claim 19, wherein the flexiblesubstrate comprises an organic resin.
 21. The light-emitting deviceaccording to claim 19, wherein the flexible substrate comprises afibrous body and an organic resin.
 22. The light-emitting deviceaccording to claim 19, further comprising a second insulating film overand being in contact with the color filter, wherein the color filter isin contact with the first insulating film.
 23. The light-emitting deviceaccording to claim 19, wherein the EL layer emits light with whitecolor.
 24. The light-emitting device according to claim 19, wherein theoxide semiconductor layer comprises indium, gallium, zinc, and oxygen.25. A light-emitting device comprising: a flexible substrate havinglight-transmitting ability; a color filter over the flexible substratewith an adhesive provided therebetween; a first insulating film over thecolor filter; a thin film transistor over the first insulating film; aninterlayer insulating film over the thin film transistor; alight-emitting element over the color filter and comprising: a firstelectrode having light-transmitting ability; an EL layer over the firstelectrode; and a second electrode over the EL layer; and a protectivefilm over the light-emitting element, wherein the thin film transistorcomprises an oxide semiconductor layer, and wherein the color filter ispositioned between the flexible substrate and the thin film transistor.26. The light-emitting device according to claim 25, wherein theflexible substrate comprises an organic resin.
 27. The light-emittingdevice according to claim 25, wherein the flexible substrate comprises afibrous body and an organic resin.
 28. The light-emitting deviceaccording to claim 25, wherein the EL layer emits light with whitecolor.
 29. The light-emitting device according to claim 25, wherein theoxide semiconductor layer comprises indium, gallium, zinc, and oxygen.30. A light-emitting device comprising: a substrate havinglight-transmitting ability; a transistor over the substrate; a colorfilter over the transistor; a light-emitting element over the colorfilter and comprising: a first electrode having light-transmittingability and being electrically connected to the transistor; an EL layerover the first electrode; and a second electrode over the EL layer; anda protective film over the light-emitting element, wherein thetransistor is overlapped with the color filter, and wherein thetransistor comprises a semiconductor layer including indium, gallium,zinc, and oxygen.
 31. The light-emitting device according to claim 30,wherein the substrate comprises an organic resin.
 32. The light-emittingdevice according to claim 30, wherein the substrate comprises a fibrousbody and an organic resin.
 33. The light-emitting device according toclaim 30, further comprising an insulating film over and being incontact with the color filter.
 34. The light-emitting device accordingto claim 30, wherein the EL layer emits light with white color.
 35. Thelight-emitting device according to claim 30, wherein the light-emittingdevice is configured to emit light from the light-emitting elementthrough the substrate.
 36. A light-emitting device comprising: asubstrate having light-transmitting ability; a transistor over thesubstrate; a color filter over the transistor; a light-emitting elementover the color filter and comprising: a first electrode havinglight-transmitting ability and being electrically connected to thetransistor; an EL layer over the first electrode; and a second electrodeover the EL layer; and a protective film over the light-emittingelement, wherein the transistor is overlapped with the color filter, andwherein the transistor comprises an oxide semiconductor layer.
 37. Thelight-emitting device according to claim 36, wherein the substratecomprises an organic resin.
 38. The light-emitting device according toclaim 36, further comprising an insulating film over and being incontact with the color filter.
 39. The light-emitting device accordingto claim 36, wherein the EL layer emits light with white color.
 40. Thelight-emitting device according to claim 36, wherein the light-emittingdevice is configured to emit light from the light-emitting elementthrough the substrate.